Characterization of Cry34/Cry35 binary insecticidal proteins from diverse Bacillus thuringiensis strain collections.

Bacillus thuringiensis crystal proteins of the Cry34 and Cry35 classes function as binary toxins showing activity on the western corn rootworm, Diabrotica virgifera virgifera LeConte. We surveyed 6,499 B. thuringiensis isolates by hybridization for sequences related to cry35A genes, identifying 78 strains.

Structure, diversity, and evolution of protein toxins from spore-forming entomopathogenic bacteria.

Gram-positive spore-forming entomopathogenic bacteria can utilize a large variety of protein toxins to help them invade, infect, and finally kill their hosts, through their action on the insect midgut. These toxins belong to a number of homology groups containing a diversity of protein structures and modes of action. In many cases, the toxins consist of unique folds or novel combinations of domains having known protein folds.

Novel Bacillus thuringiensis binary insecticidal crystal proteins active on western corn rootworm, Diabrotica virgifera virgifera LeConte.

A new family of insecticidal crystal proteins was discovered by screening sporulated Bacillus thuringiensis cultures for oral activity against western corn rootworm (WCR) larvae. B. thuringiensis isolates PS80JJ1, PS149B1, and PS167H2 have WCR insecticidal activity attributable to parasporal inclusion bodies containing proteins with molecular masses of ca.

Insecticidal proteins from Bacillus thuringiensis protect corn from corn rootworms.

Field tests of corn co-expressing two new delta-endotoxins from Bacillus thuringiensis (Bt) have demonstrated protection from root damage by western corn rootworm (Diabrotica virgifera virgifera LeConte). The level of protection exceeds that provided by chemical insecticides. In the bacterium, these proteins form crystals during the sporulation phase of the growth cycle, are encoded by a single operon, and have molecular masses of 14 kDa and 44 kDa.

Structure, function and engineering of Bacillus thuringiensis toxins.

Nature has provided potent insecticidal toxins as fermentation products of many Bacillus thuringiensis strains. Elucidation of structure-function relationships for this class of natural toxins is in its early stages. Both direct experimentation and application of theoretical structure-function principles emerging from the rapidly growing field of protein structure are accelerating understanding of these toxins.

Expression of the cryIB crystal protein gene of Bacillus thuringiensis.

The cryIB gene of Bacillus thuringiensis subsp. thuringiensis HD-2 codes for a Mr 139492 protein that is lethal to certain lepidopteran larvae. We used primer extension to map transcriptional initiation sites and found that cryIB was transcribed from two sites that are activated at different times during sporulation.

Specificity-determining regions of a lepidopteran-specific insecticidal protein produced by Bacillus thuringiensis.

The lepidopteran-specific, insecticidal crystal proteins of Bacillus thuringiensis vary in toxicity to different species of lepidopteran larvae. We report studies of CryIA(a) and CryIA(c), two related proteins that have different degrees of toxicity to Heliothis virescens yet very similar degrees of toxicity to Manduca sexta. The amino acid differences between these proteins are located primarily between residues 280 and 722.

Expression of a cloned Bacillus thuringiensis crystal protein gene in Escherichia coli.

The expression in Escherichia coli of a cloned crystal protein gene from Bacillus thuringiensis was investigated through the use of fusions of the crystal protein gene promoter to beta-galactosidase and catechol oxidase genes. Analysis of deletion and insertion derivatives of the crystal protein gene promoter showed that a region of B. thuringiensis DNA located between 87 and 258 base pairs upstream from the transcription initiation site caused reduced transcription from this promoter.

The molecular biology of parasporal crystal body formation in Bacillus thuringiensis.

Data obtained using several experimental methods (curing, transconjugation, cloning, and hybridization) indicate that crystal protein genes in many subspecies of BT that are toxic to lepidopterans are located on one or more large plasmids; in some subspecies, the gene may be located on the chromosome. Detailed mapping has shown that in three plasmids (each from a different strain) the genes are surrounded by multiple copies of two repeated DNA elements; the arrangement of these elements is the same in the three plasmids. An analysis of the sequence of one of these repeated DNAs strongly suggests that it contains a transposase.

Delineation of a toxin-encoding segment of a Bacillus thuringiensis crystal protein gene.

Crystals of Bacillus thuringiensis subsp. kurstaki HD-1-Dipel contain a Mr 134,000 protoxin which can be cleaved by proteolysis to a peptide of Mr approximately 70,000; this peptide is lethal to lepidopteran larvae. We have analyzed the peptides produced by recombinant Escherichia coli strains bearing deletions and fusions of the protoxin gene in order to delineate the portion of the gene which encodes the toxic peptide.

The amino acid sequence of a crystal protein from Bacillus thuringiensis deduced from the DNA base sequence.

We have determined the nucleotide sequence of a 4222-base segment of DNA which contains the promoter, the coding region, and the terminator of a crystal protein gene cloned from a Bacillus thuringiensis plasmid. A sequence of 1176 amino acids encoding a Mr 133,500 peptide was deduced from the single open reading frame. This protein-coding region was analyzed for codon usage, predicted hydropathy, and predicted secondary structure.

Diversity of locations for Bacillus thuringiensis crystal protein genes.

The location of crystal protein genes in 22 crystalliferous Bacillus thuringiensis strains representing 14 subspecies was investigated by hybridization of an intragenic restriction fragment from a cloned crystal protein gene to whole plasmid preparations. Hybridization was found to a single plasmid in eight strains, to more than one plasmid in seven strains, and to one or both of two large, unresolved plasmids in two strains. The sizes of the hybridized plasmids ranged from 33 to over 150 megadaltons.

Transcriptional and translational start sites for the Bacillus thuringiensis crystal protein gene.

The nucleotide sequence of the promoter region and part of the coding region of the crystal protein gene from Bacillus thuringiensis var. kurstaki HD-1-Dipel has been determined by analysis of a recombinant plasmid from Escherichia coli. The start points for transcription of the gene in B.

Cloning and expression of the Bacillus thuringiensis crystal protein gene in Escherichia coli.

Sau 3A1 partial digestion fragments from Bacillus thuringiensis var. kurstaki HD-1 plasmid DNA were ligated into the BamHI site of the cloning vector pBR322 and transformed into Escherichia coli strain HB101. Colonies presumed to contain recombinant plasmids were screened for production of an antigen that would react with antibody made against B.